are your motherboard drivers in the pcie slot updated to accept the new videocard. Make sure you motherboard drivers are loaded up before trying to fire up your videocard. Download & run specy to check what drivers your missing & DDU to uninstall the Radeon drivers. You wanna make sure your motherboard will accept your card first. More details be nice to help answer a bit easier.

If I put in the BIOS "Primary Graphics Adapter OnBoard", the GPU works but I can't play videogames with It because the Primary Graphics Adapter is OnBoard. With Rainbow Six Siege I can play with It without any problem because there's an option that allows me to choose which GPU to use.